Japan's Morimura Corporation and Morimura Chemical have recently developed a new technology that utilizes a combination of printing technology and gold plating to produce wireless tag (RFID tag) antenna patterns. The technology was demonstrated at the recently held Auto ID Exhibition. No etching is used, which means that the material can be cut off and the wireless tag antenna can be produced at a lower cost. Morimura Commercial plans to use this technology to mass-produce wireless tag antennas in the second half of 2006.
The manufacturing process of the RFID tag antenna is as follows: (1) First, a water-soluble special ink developed by Morimura Chemical Co., Ltd. is used to print an antenna on a flexible substrate formed with a pattern of an antenna using PET or the like using a printing technique or an inkjet technique. Pattern; (2) Then put the flexible bottom plate into the plating bath. After the above process, a copper film can be formed on the wiring pattern drawn with the special ink. The special ink used here refers to "a solution made by dissolving two kinds of metals into particles having a particle diameter of several tens of nanometers and then dissolving them in water" (Director and General Manager of RFID Business Promotion Center, Morimura Corporation's Resins & Chemicals Business Unit, Shinei Saiman) ).
This method does not etch the copper foil, ie the "subtractive" process, but merely places the material on the base plate and is therefore often referred to as an "additive" method. In addition, the copper wiring itself is formed using electroplating technology and does not require high-temperature sintering such as heat treatment. Therefore, a low heat-resistant flexible floor material can be used. “The resistance between the two ends of the antenna is less than 0.4Ω. Although it is very large from the bulk copper, there is no problem as a wireless tag antenna” (inside).
For the processing accuracy of the wiring, "If you use the printing technology in the initial process, you will be able to achieve the 80μm wiring interval. However, the inkjet technology has droplets, so the accuracy is slightly reduced," and the wiring interval is slightly wider. a little.
Past antenna formation techniques have their own advantages and disadvantages
In the past, wireless tag antenna pattern formation technology was roughly divided into three types, each having advantages and disadvantages. One is the same as this time, the use of electroplating techniques to form copper wiring. However, a dry etching technique or a wet etching technique is used in the formation of the wiring pattern. For example, in a method using a wet etching technique, usually after the copper foil is stuck on the flexible substrate, the mask of the wiring pattern is printed on the substrate, and then the solution is poured, and the part of the copper without the mask is melted away. .
The second technique is to perform heat treatment after directly drawing a wiring pattern. The reason why the heat treatment is performed is because if only silver (Ag) paste or copper paste is applied, the resistance is too large to be used as an electrical wiring. Most of the heat treatment is performed under conditions of more than 200 degrees, and low-heat-resistant PET cannot be used as a base plate. However, on September 5, 2005, the Japan Industrial General Research Institute announced that it has developed another method called “pressure heat treatment” that is different from high-temperature sintering and solves the temperature problem.
The third technique refers to a vacuum process such as vapor deposition or vacuum sputtering. The manufacturing equipment used in this method is expensive and there is a problem of how to reduce the cost of the label.
Source of information: India Tradelink
